1. Field of the Invention
The invention relates to the field of gears and in particular, to angled gears where in addition to gearing ratios, an angle is provided between axes of rotation of the driving and driven gears is realized.
2. Description of the Prior Art
Gear combinations for providing gear ratios and changes in the direction of the axis of rotation are well known to the art and are generally realized through various types of bevel gears. Examples of such bevel gears can be found in many application, such as shown in Calvert, "Angle Meshing Gear," U.S. Pat. No. 4,167,127 (1979). Such right angle gearing has also been employed in a number of applications in which one of the gears is a toothed gear, having a pin gear with a plurality of circumferentially spaced studs or pins instead of a shaped gear tooth. Examples of pin gears can be found, for example, in Sager, "Angle Gearing," U.S. Pat. No. 602,629 (1898); Tamiya, "Differential Gearing," U.S. Pat. No. 4,602,527 (1986); and Brooks, "Power Transmission Means," Reissue 22,555 (1944). The use of pin gears in combinations with various types complex machined grooves can be found in McCartin, "Spherical Thread and Pin Gear Reduction," U.S. Pat. No. 3,495,470 ( 1970); Claud-Mantle, "Indexing Mechanism," U.S. Pat. No. 2,933,964 (1960); Hunt, "Rotary Cam Gear," U.S. Pat. No. 498,552 (1893); Winter, "Multiple Speed Gear Transmission and Tooth Construction," U.S. Pat. No. 3,075,397 (1963); and Koll, "Stufengetriebe," Austrian Patent 149,799 (1937). Pin gears have also been used in hybrid pin and hole combinations such as shown by Fuchs, "Coacting Pin-in-Hole Gears," U.S. Pat. No. 3,661,028 (1972).
The use of gear-like structures in dish-shaped or doorknob-shaped bodies are also illustrated in the application of Stokes et al, "Motion Transmitting Device," U.S. Pat. No. 705,624 (1902); and Mohr et al, "Angular Drive Intermittent Motion Mechanism," U.S. Pat. No. 5,197,354 (1993).
Each of these pin gear combinations have various advantages and disadvantages, but they all share in common a certain bulkiness which makes their use in applications where compactness or size limitations are a critical requirement difficult. In order to make such gearing combinations useful in such applications, their overall size must be reduced. If the size is reduced, then the structural elements of the gearing combination similarly are reduced in size and hence strength. The use of such gearings in small spaces in, for example, small motors, wherein the gearing must be rugged and driven at high speed with relatively substantial forces in torques becomes problematic.
Often such pin gear combinations do run smoothly due to the fact that at any one instant only a few pins are fully or even partially engaged.
In addition, if different gearing ratios are required, it is usually necessary to change the size of at least one of the gears and hence the volume which the gear combination occupies.
Therefore, what is needed is some type of a pin gear combination which allows different gear ratios to be realized between the gears in the combination and also a change of direction between the driving and driven shaft angles that can be used in applications where space is a limitation or is fixed, and which runs smoothly.